Plastic egg cartons



March 21, 1967 D. c. TRIMBLE PLASTIC EGG CARTONS 2 Sheets-Sheet 1 FiledApril 8, 1966 DAVID C. TRIMBLE D. C. TRIMBLE PLASTIC EGG GARTONS March23, 1967 2 Sheets-$heet 2 Filed April 8, 1966 DAVID C.TR|MBLE FIG.5

United States Patent 3,310,217 PLASTIC EGG CARTONS David C. Trimble,Yorklyn, Del., assignor, by mesneassignments, to Hercules Incorporated,New Castle County, Del., a corporation of Delaware Filed Apr. 8, 1966,Ser. No. 541,200 3 Claims. (Cl. 229-25) The present invention relates toan egg carton, and has for an object to provide means in an egg cartonfor resisting twisting or warping of the carton about its longitudinalcenter line, as when the loaded carton is lifted by one corner thereof.Further objects of this invention are to provide such a means which canbe formed integrally in the carton and is therefore inexpensive, andwhich is sufliciently strong and durable so that it will functiondependably and efficiently throughout the useful life of the carton.

While the present invention is useful in egg cartons of other materials,it has been designed primarily for use with an egg carton such as thatwhich forms the subject matter of my co-pending United States patentapplication Ser. No. 541,188, filed Apr. 8, 1966, that is, an egg cartonmolded from a sheet of foamed or expanded plastic material. Inparticular, the present invention is designed for use with an egg cartonhaving a base member that is divided by partitions into a plurality ofegg-receiving pockets, and also having a pair of cover members each ofwhich is adapted to cover a portion of the base member and is hinged tothe base member along one of the longitudinal side edges thereof so thatit can be swung inwardly, together with slotted posts for receiving anedge portion of each cover member to position and frictionally to gripthe same, thereby holding the cover members in closed position. Theobjects of the invention have been attained by the use of notches in thecover members, which notches extend out of the plane of the side wall ofthe cover member and are adapted to engage against the posts to preventsliding of the cover member relative to the posts. A further advantagederived from this invention is that the notches, by forming the same toopen on the top of the cover members, may serve as thumb holes tofacilitate opening the car-ton.

With the above and other objects in view, a presently preferredembodiment of the invention is hereinafter described with reference tothe accompanying drawings in which:

FIG. 1 is a perspective view of an egg carton embodying the presentinvention with one of the cover members illustrated in phantom in theopen position and partly broken away.

FIG. 2 is a fragmentary view in top plan of the egg carton of FIG. 1.

FIG. 3 is a fragmentary transverse sectional view taken substantially onthe line 3-3 of FIG. 2.

FIG. 4 is a fragmentary longitudinal sectional view taken substantiallyon the line 44 of FIG. 2 and illustrating the carton with the coverthereof in closed position.

FIG. 5 is a fragmentary transverse sectional view similar to FIG. 3 buton an enlarged scale and with the cover members closed.

With reference to the drawings, the present invention is illustrated asembodied in an egg carton thermoformed from a sheet of any suitablefoamed plastic material, such as polystyrene, polyethylene,polypropylene, copolymers of ethylene and propylene and the like, oralternatively, formed from other materials such as pulp. The illustratedcarton comprises a tray-like base member 1 and a pair of generallyU-shaped cover members 2, each of which is hinged along one edge to anupper longitudinal edge of the base member 1 by a hinge 3 and is adaptedto be 3,310,217 Patented Mar. 21, 1967 swung between a closed positionoverlying the base memher and an open position in which the open top ofthe base member is exposed. With a carton of foamed plastic material,the hinge 3 may be of the type and may be formed in the manner disclosedand claimed in my copending United States patent application Ser. No.541,189, filed Apr. 8, 1966.

The base member 1 includes a pair of opposed side walls 4 and a pair ofopposed end walls 5, which are discontinuous as noted below and whichare tapered outwardly or diverge in the direction away from the bottomplane 6 of the base member at angles of approximately sixty degrees tothe plane 6. The walls 4 and 5 also have the upper edges thereofdisposed in and thereby define a top plane 7 that is substantiallyparallel to the bottom plane 6.

The illustrated carton is of the standard 2 x 6 type in which there areone dozen egg-receiving pockets 9 arranged in two rows of six pocketseach. The means for dividing the base member 1 to provide the pockets 9comprises a longitudinal partition 10 and five transverse partitions 11,which intersect the side walls 4 and end walls 5, thereby rendering thesame discontinuous. The partitions 10 and 11 are inverted V-shaped withupper edges 12 and 13, respectively, and side walls 14 and 15 that, likethe side walls 4 and end walls 5 of the base member 1, are inclined atangles of about sixty degrees to the bottom plane 6 of the carton. Thepockets 9 are thus each defined by four opposed side walls, i.e., theside walls 4, the side walls 14 of the partition 10 and a pair of theside walls 14 of the partitions 11, except for the end pockets whereinthe end wall 5 is used in lieu of one of the walls 14, all of whichwalls diverge upwardly from a substantially square bottom wall 16disposed in the bottom plane 6 and which may be cushioned.

At the intersection of the longitudinal partition 10 with each of thetransverse partitions 11, there is provided a post which is either aflat-topped, cover-supporting post 17 or a slotted cover-retaining post18, there being in the illustrated embodiment of the invention anarrangement such as is disclosed and claimed in my co-pending UnitedStates patent application Ser. No. 541,187, filed Apr. 8, 1966, that is,an alternating arrangement of five posts 17 and 1:8 consisting of threecover-retaining posts 18 located on each at the center and the two outerpositions and two cover-supporting posts 17 located one each at the twointermediate positions. Each of the posts 17 has a flat top 19 anddepending walls 29.. The tops 19 are in the top plane 7 of the basemember 1 and are substantially square with the corners thereof centeredover the upper edges 12 and 13 of the partitions 10 and 11. Thecoverretaining posts 18 have walls 21 that are also arranged in apattern that is substantially square in transverse crossseetion with thecorners thereof disposed directly over the upper edges 12 and 13 of thepartitions 10 and 11. The posts 18 rise above the top plane 7 of thebase member 1 and are provided with slots 22 that extend inwardly fromthe upper or free end thereof to a point at least level with butpreferably slightly below the top plane 7 of the base member 1, theslots 22 being arranged longitudinally of the base member 1 and fromcorner-to-corner of the posts 18 or, in other words, with the centerline thereof in a plane that is normal to the top plane 7 and includesthe upper edge 12 of the longitudinal partition 10. The posts 18 alsoinclude tops 23 that slope inwardly and downwardly toward the slots 22from the outermost corners thereof for the purpose of directing theedges of the cover members 2 into the slots 22.

The walls 20 and 21, as Well as corresponding walls 24 and 25 thatare-formed respectively between the walls 4 and 15 and between the walls5 and the adjacent walls 4 and 14, serve as corner walls for the pockets9 and act to confine the eggs more closely in the pockets and to provideresilience so that the walls 4, 5, 14 and 15 can be flexed outwardly toaccommodate eggs of a size larger than that for which the pockets wereprimarily dimensioned and thus providing a single carton that issufiiciently versatile that it can be used with a number of differentsizes of eggs. The corner walls 20, 21, 24 and 25 may be planar or maybe slightly convex and are arranged at an angle of substantiallyseventy-five degrees to the bottom plane 6 of the base member 1.

The cover members 2 are each generally U-shaped in transversecross-sections and include a top wall 26 and a depending skirt portionincluding an inclined side wall 27, which is inclined relative to thetop wall 26, a normal side wall 28, that is normal relative to the topwall 26 and end walls 29 extending between the two side walls. The covermembers 2 are formed integrally with the base member 1 and are hingedalong the edge of the inclined side wall 27 to the upper or free edge ofthe side wall 4 by means of the hinge 3.

The cover members 2 are dimensioned such that when they are closed, thenormal side walls 28 are substantially normal to the top plane 7 of thebase members 1 with the outer surfaces of the two cover memberssubstantially in contact or in surface-to-surface abutting relation toeach other and the top walls 26 are substantially in spaced parallelrelation to the plane 7. The closed position of the cover members 2 isas illustrated in FIG. 5, that is, with the edge portions of the sidewalls 28 inserted in the slots 22 of the posts 18 and the free edgesthereof seated on the tops 19 of the posts 17. At the same time, thethickness of that portion of each of the walls 28 that is receivedWithin the slots 22 is more than one-half the width of the slots 22 sothat the combined thickness of the wall portions is greater than thewidth of the slot, thus requiring that they be forced into the slots andinsuring that they will be frictionally retained therein.

For a more detailed description of the specific configuration anddimensions of the base member 1 and the cover members 2, and of thefunctions and advantages thereof, reference is made to my above notedco-pending application Ser. No. 541,188. Formed in the wall 28 of eachof the cover members 2 is a pair of notches 30, each of which issubstantially semi-conical with the base thereof at the top wall 26 ofthe cover member and the apex thereof adjacent to the free edge of thewall 28. The notches 30 are designed to receive the thumbs of the userto facilitate opening the cover members 2, which, of course, wouldotherwise be quite difiicult in view of the fact that the side walls 28of the cover member 2 are in abutting relation and afford no opening orhand-hold by means of which the user can easily grasp the cover members2 to open the same. In the illustrated embodiment, the notches 30 ineach of the cover members are opposed so that the total thumb hole issubstantially conical.

The notches 30 also are designed to add stiffness to the carton and toprevent twisting or warping thereof, as for example, when the loadedcarton is lifted by one corner. For this reason, the notches 30 aredisposed longitudinally of the wall 28 on opposite sides of andsubstantially in engagement with one. or more of the posts 18, moreparticularly, in the illustrated embodiment, the notches 30 are locatedinwardly of the two posts 18 at the opposite ends of the base member 1.Thus, the one notch 30 of each wall 28 at the one end of the carton 4will, through engagement with the post 18, prevent sliding of that wall28 in the one direction relative the post 18 and the notch 30 at theother end of the carton will similarly prevent sliding of the wall 28 inthe other direction.

What I claim and desire to protect by Letters Patent is:

1. An egg carton comprising a tray-like base member with an open top ina top plane and having longitudinal side walls and a plurality ofpartitions dividing the same into a plurality of egg-receiving pocketsarranged in two rows longitudinally of the base member, a plurality ofposts disposed along the longitudinal center line of the base member andextending above the top plane of said base member, said posts havingslots arranged longitudinally of the base member and extending inwardlyfrom the free edges thereof through that portion of said posts disposedabove the top plane, and a pair of complemen-tal cover members each ofwhich includes a fiat top wall that is disposed substantially in spacedparallel relation to the top plane of the base member when said covermembers are closed and overlies substantially one-half of said basemember, and substantially planar side walls with substantially straightfree edges depending from the longitudinal edges of said top wall, eachof said cover members being hinged to said base member along the freeedge of one of said side walls and having the other of said side wallsdisposed in surface-to-surface abutting relation with the correspondingside wall of the other cover member and provided with edge portions thatare adapted to be received within said slots when said cover members areclosed, said other side wall of one of said cover members havingportions displaced out of the plane of the side wall in the directionaway from the abutting side wall to provide a plurality of notches withone notch in engagement with one of said posts on one side thereoflongitudinally of the base member and another notch in engagement withone of said posts on the opposite side thereof longitudinally of thebase member, whereby the engagement of said notches with said posts willprevent relative movement between the respective edge portions of saidcover members longitudinally of the base member, said notches extendingto the plane of the top wall to define thumb holes to facilitate openingof said cover members.

2. An egg carton in accordance with claim 1 in which said notches aresubstantially semi-conical with the base thereof in the plane of the topplate of the cover members, thereby providing thumb holes to facilitateopening of said cover members.

3. An egg carton in accordance with claim 1 in which said posts includetwo posts disposed adjacent to each end of the base member, and saidnotches include a notch formed in each cover member inwardly of eachpost to define an opposed pair of notches adapted to engage the inneredge of each post.

References Cited by the Examiner UNITED STATES PATENTS 2,466,579 4/1949Cox 229-2.5 2,634,039 4/1953 Schwertferger 229-2.5 X 2,778,558 1/1957Butterfield 22929 2,933,227 4/1960 Vahle 2292.5 2,971,685 2/1961 Treida229-29 X 3,093,286 6/1963 Brickner et al. 229-2.5 3,191,844 6/1965Comstock 2292.5

GEORGE O. RALSTON, Primary Examiner.

1. AN EGG CARTON COMPRISING A TRAY-LIKE BASE MEMBER WITH AN OPEN TOP INA TOP PLANE AND HAVING LONGITUDINAL SIDE WALLS AND A PLURALITY OFPARTITIONS DIVIDING THE SAME INTO A PLURALITY OF EGG-RECEIVING POCKETSARRANGED IN TWO ROWS LONGITUDINALLY OF THE BASE MEMBER, A PLURALITY OFPOSTS DISPOSED ALONG THE LONGITUDINAL CENTER LINE OF THE BASE MEMBER ANDEXTENDING ABOVE THE TOP PLANE OF SAID BASE MEMBER, SAID POSTS HAVINGSLOTS ARRANGED LONGITUDINALLY OF THE BASE MEMBER AND EXTENDING INWARDLYFROM THE FREE EDGES THEREOF THROUGH THAT PORTION OF SAID POSTS DISPOSEDABOVE THE TOP PLANE, AND A PAIR OF COMPLEMENTAL COVER MEMBERS EACH OFWHICH INCLUDES A FLAT TOP WALL THAT IS DISPOSED SUBSTANTIALLY IN SPACEDPARALLEL RELATION TO THE TOP PLANE OF THE BASE MEMBER WHEN SAID COVERMEMBERS ARE CLOSED AND OVERLIES SUBSTANTIALLY ONE-HALF OF SAID BASEMEMBER, AND SUBSTANTIALLY PLANAR SIDE WALLS WITH SUBSTANTIALLY STRAIGHTFREE EDGES DEPENDING FROM THE LONGITUDINAL EDGES OF SAID TOP WALL, EACHOF SAID COVER MEMBERS BEING HINGED TO SAID BASE MEMBER ALONG THE FREEEDGE OF ONE OF SAID SIDE WALLS AND HAVING THE OTHER OF SAID SIDE WALLS